1. Field of the Invention
This invention relates to a guidance system for an agricultural implement and more particularly to a means for mounting a guidance system forwardly of the implement adjacent one end thereof.
2. Description of the Prior Art
In many farming operations, agricultural implements such as cultivators, planters, fertilizer spreaders, and sprayers are pulled by tractors and are used in connection with row crops. It is extremely important that the implement be properly positioned with respect to the row so that the implement does not damage the crop. In ridge till operations, it is extremely important that the planter be centered with respect to the ridge so that the seeds are properly positioned in the ridges. It is also important that the fertilizer applicators and sprayers also be properly positioned with respect to the growing crop in the ridge. In cultivating operations, it is very important that the cultivator be properly positioned with respect to the rows to prevent damage to the growing crop.
Many types of guidance devices have been previously provided for use with an agricultural implement so that the implement will be moved laterally with respect to the tractor should the implement be out of alignment with the rows being planted, cultivated, etc. One type of guidance control apparatus is disclosed in U.S. Pat. No. 4,930,581 issued Jun. 5, 1990 to Fleischer et al. In the device of the '581 patent, the position of the implement is sensed by a pair of sensing wands which engage the emerging crops of adjacent rows. Should the implement move laterally with respect to the row for one reason or another, the wand resolver, which is operatively connected to the sensing wands, will generate an electrical signal to actuate a hydraulic circuit so that the hitch connecting the implement and the tractor will pivot about a vertical axis to laterally shift the implement.
A guidance system which is believed to be very similar, if not identical to the device disclosed in U.S. Pat. No. 4,930,581, is manufactured by Fleischer Manufacturing, Inc., Columbus, Nebr., under the trademark BUFFALO SCOUT.
Another type of guidance system is manufactured by Lincoln Creek Manufacturing Co., Inc. of Phillips, Nebr., under the trademark THE GUIDE. It is believed that the guidance system manufactured by Lincoln Creek Manufacturing Co., Inc. laterally shifts the hitch which connects the implement and the tractor when the implement is sensed to be out of alignment with the row.
Yet another type of guidance control is manufactured by Sunco Marketing of North Platte, Nebr., under the trademark ACURA TRAK. Other types of guidance systems are manufactured by Orthman Manufacturing Co., Inc. of Lexington, Nebr. under the trademarks CQH SWINGER and MP III TRACKER.
In the prior art guidance systems described hereinabove, the systems include guide rods, guide weights, sensing wands or the like which are normally located at the center of the implement and are normally positioned behind the draw bar of the implement and dragged through the field. It is believed that the prior art guidance systems suffer from certain disadvantages in that the guide weights, wands, rods, etc. are not able to accurately sense the position of the implement due to the condition of the field which may have clods, rocks, crop residue, etc. in the rows which adversely effects the sensing operation, Further, by positioning the sensing means behind the draw bar, it is believed that the sensing means suffers from a slight delay in sensing the position of the implement since the front portion of the implement will have already passed over that which is being sensed.